Make BlitzForge Git hooks portable across contributor environments

[CoreyRDean]

Non-technical summary

This makes BlitzForge's shipped local Git hooks usable across contributor environments instead of only on Windows shells. Contributors can now opt into the repo hooks with one Git config command, and the README explains what those hooks actually do.

Why this matters now: the live develop docs said the full test suite ran as a local pre-commit hook, but on macOS the hook immediately failed because it hard-called cmd.exe, and the post-commit cleanup logic depended on GNU-only shell behavior. That made the contributor workflow claim stronger than the implementation.

After this change, the system is better because the documented local hook workflow is honest, cross-platform, and reproducible for fresh clones.

Technical summary

• Reworked .hooks/pre-commit to resolve the repo root and dispatch to test.bat on Windows shells or test.sh on Unix-like hosts.
• Reworked .hooks/post-commit to use portable Bash + awk cleanup instead of GNU-specific sed -i and head -c -1 behavior.
• Made the post-commit cleanup handle root commits and skip deleted files safely.
• Updated ReadMe.md to document git config core.hooksPath .hooks, explain the shipped hook behavior, and stop implying hooks are automatic.
• Breaking changes: none.

Additional notes

• Trade-off: this keeps the existing hook model instead of introducing a dedicated hook installer script, which keeps the increment small and aligned with the current repo structure.
• Deferred follow-up: if the project wants hooks enabled automatically for all contributors, a bootstrap/setup command would be the next step.
• Remaining gap: the Windows batch path was validated by dispatch logic and existing script compatibility, but not executed live in this macOS environment.